ipwireless: make more use of pcmcia_loop_config()

Within the pcmcia_loop_config() callback, we already have all
tuple data available we need. Also add a fix to release the IO
resource (at least within pcmcia_loop_config() error path).

CC: Jiri Kosina <jkosina@suse.cz>
CC: David Sterba <dsterba@suse.cz>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>